a) Field of the Invention
This invention relates to aromatic polymers which are amorphous and readily soluble in organic solvents, can be formed with a wide range of glass transition temperatures and can be cast to provide tough, transparent, flexible films; copolymers can also be synthesized; the invention also relates to processes for producing the polymers. The invention is more especially concerned with polyketones, polyphthalazines and polyisoquinolines.
b) Description of Prior Art
Polyetherketones that are para-substituted are commercial materials with modest glass transition temperatures and relatively high melting points; polyetherketones with meta substitution have also been synthesized (P. M. Hergenrother et al, J. Polymer Prepr.--[Am. Chem. Soc., Div. Polym. Chem.] 1985, Vol. 26, page 174).
Polyquinolines have been synthesized (J. K. Stille et al, Polym. Chem. Ed., 1975, Vol. 13, page 2233; Macromolecules, 1976, Vol. 9, pages 489 and 496) and exhibit high stiffness and high glass transition temperatures. These polyquinolines are relatively insoluble. One approach to improving the solubility without loss of thermal stability has been the introduction of flexible groups into the polymer backbone, and depending on the chemical repeat unit structure, high molecular weight polyquinolines exhibit a Tg ranging from 250.degree. to 400.degree. C. These polyquinolines are produced by a complex synthesis from costly starting materials and have not been exploited.